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July 10, 1945. Q. M. KLlNE INTEREST. CALCULATOR Filed Aug. 14, 1943 Q E E @i E E E tudinal channel I4. One aperture II-A isV located in each longitudinal channel, and is aligned longitudinally with the bottom apertures II in each of the series of such apertures which extend across the width of each longitudinal channel.

A plurality of removable slide members I5 are provided, one each for each longitudinal channel` In the present instance four such slide members are provided for the four longitudinal channels here shown. Each of the four longitudinal channels is labeled on the face I so as to indicate the principal sum which is the basis for the selection of the data' placed on the movable slide member I to be carried in said channel. In the present instance these longitudinal channels represent respectively thousands, hundreds, tens and dollars of the principal sums for which interest computations are to be made. The four slide members I5 are correspondingly labeled thousands, hundreds, tens and dollars so that the proper slide is in all instances readily selected for insertion in the proper channel.

Each slide I5 as shown in Figs. 3, 4, 5 and 6, exhibits the interest calculating data on the face portions thereof in `three longitudinally extending columns, and in ten inclined staggered vertical columns corresponding to ten longitudinally adjusted positions in which each slide member may be used so as to bring into registry with the apertures I I-A the ten digits 16 which are placed thereon to represent the ten units of the particular portion of the principal sum. Each slide, therefore, represents principal amounts of from zero to nine, one slide is calibrated in terms of dollars, another in terms of tens, another in terms of hundreds and another in terms of thousands. Thus the slide member I5 will be seen to contain the desired data in such a manner that when the correct number of units of the principal sum is brought in registry with the apertures II-A, the data which is brought in registration with the apertures II and is displayed therein will correspond to the amount of interest calculated at the rate of 21/2% for the various time intervals represented by the vcrtlcal columns in which the apertures II are arranged. The staggered arrangement of the longitudinally adjacent apertures II separates the vertical columns in such a manner as to avoid the possibility of errors which might occur if the data for each time interval was aligned longitudinally with the data in the vertical column adjoining the adjacent time interval column. The. arrangement is such that by a single `adjustment of each of the slide members I5, all of the required data to make the interest calculation for various preselected time intervals, is displayed at one time through the apertures I I provided in the face plate I Il.

The data on each member I5 represents calculated interest amounts at a preselected rate and these figures when arranged as shown in Figs. 3, 4, 5 and 6 are readily brought into positive alignment with the apertures II in the face portion I0 to provide the data from which the interest calculation is made. By the substitution of other slide members for the separate and readily removable slide members I5, it is possible to provide other data which may be displayed through the apertures II in a similar manner so as to permit the making of various types of calculation by the simple expedient of providing sets of slide members I5 on which the desired data is provided. Thus while there is here shown by way of example an interest computer f for computing interest at the rate of 21/2%, it will be seen that other slide members may be provided having the interest calculating data required for making computation at other rates. By substitutionofsuch other members for the member I5 here shown, it will be seen that interest may be calculated at any desired rate by the device of the present invention. For example, if a universal interest calculator is desired, slides similar to the slides I5 may be provided containing data computed for various interest rates for the time intervals shown on the face portion of the calculator and for the particular amounts represented by each slide member. Thuslsimply by substituting one set of slide members for another set of slide members, interest calculations at various rates may be made readily.

The device of the present invention may be readily used in making interest calculations, for example in building and loan or savings account records. Likewise, the device may be used in figuring interest due on land contracts, mortgages, and the like. When used, the slide members I5 are moved longitudinally of the face member I 0 so as to bring into registry in the vertical column of apertures II-A the amount of the principal sum. In Fig. 1 the device is shown adjusted to provide interest calculations at the rate of 21/2% for a principal sum of $4,121.00. In this instance the slide I5 in the longitudinal column representing thousands has been moved to the right so as to bring the numeral four into registry in the aperture I I-A, the slide I5 in the longitudinal column representing hundreds has been moved to the right to bring the numeral one into registry with the aperture II-A therein, the slide I5 in the longitudinal column representing tens has been moved to the right to bring into position in the aperture I I-A the numeral two and the slide I5 in the longitudinal column representing dollars has been moved to the right to bring into registry in the aperture II-A the numeral one. Thus by looking downwardly on the vertical column of apertures II-A it will be seen instantly that the principal sum for which the interest calculation is to be made is $4,121.00. By noting the data on the end portion of each of the slide members I5, it will be seen that the interest is to be computed at the rate of 21/2%. The six vertical columns on theace portion of the calculator represent respectively the periods one month, two months, three months, four months, five months and six months, and by totaling any one i of the vertical columns, the total'interest computation for such time period is readily made. For example interest on $4,121.00 at 21/% for one month would be computed by adding the figures $8.35, $.21 and $.04, which appear in the vertically arranged apertures II under the column headed one month.

If the interest period is greater than the time period shown in any one of the vertical columns, it may be necessary to total the interest in more than one column and to add such amounts ln order to complete the interest calculation. Thus for example, if the time interval for which interest is to be calculated is nine months, the interest data showing in the vertical column headed six months is totaledl together with the interes-t data appearing under the column three months.

While the present calculator is here shown by way of example for the computation of interest in a plurality of selected monthly periods, itis to be understood that the device may be readily adapted for the computation of interest for other time periods by the simple expedient of changing the time indicating data on the face portion of the device and by providing slide members I5 on which the desired data is suitably arranged.

While a very important field for use of the present device isV that of interest calculations, it is to be understood that the device may be used for various types of calculations or mathematical computations. By changes in the location and arrangement of the apertures of H and Il-A and by corresponding changes in the arrangement of the data carried on the removable slide members I5, the device is readily adaptable for use in many other elds.

From the foregoing it will be seen that the computing device of the present invention possesses a simplled design providing a simplied and positive operation which permits the ready calculation and computation of tabulated information by a single adjustment of each of the slide members l5 so as to vary the principal amount of the calculation. The desired data is displayed in a plurality of vertical columns from which the displayed information may be readily taken by the user of the device. 'I'he device is positive in its operation and the data appearing thereon is so arranged that errors in transcribing the data and in the use thereof for the making of computations are very largely avoided.

Having thus described my invention, I claim:

1. A device for computing interest at a given rate on variable sums for a plurality of different predetermined time intervals, and comprising a body portion divided into a plurality of longitudinally extending separated channels, a face por tion enclosing one face of each of said channels, and having a series of fixed apertures therein communicating with said channels and arranged in a plurality of vertical columns, each of which is marked to correspond to a single time interval for which interest is to be computed, and having other apertures arranged' in a separate vertical column to indicate the principal sum upon Which interest is to be computed, a removable slide in each of said channels, each of said slides carrying interest calculations computed at a given rate and figures denominating various principal sums on the face thereof, and adapted for movement longitudinally of one of said channels to bring selectively into alignment simultaneously with all of said apertures communicating with said channel, an interest calculation corresponding to each of the predetermined time intervals indicated thereon for the adjusted principal sum shown in the aperture arranged to indicate said sum.

2. A computing device as claimed in claim l and further characterized in that six vertical columns of apertures are provided to represent respectively six time intervals and in that the longitudinally adjacent apertures in said column are arranged in vertically and horizontally staggered relation to each other.

3. A` computing device as claimed in claim 1 and further characterized in that the body portion comprises a face portion and a back portion secured in spaced relation to each other, and in that a plurality of longitudinally extending spacer members are provided to act as partitions for dividing said space into a plurality of separate longitudinal channels. i

4. A Computing device as claimed in claim 1 and further characterized in that the data required for the computation is arranged in a plurality of separate columns extending longitudinally of each slide member and spaced to display said data in the said apertures arranged in said vertical columns.

5. A computing device as claimed in claim 1 and further characterized in that a plurality of vertical columns of apertures are provided to represent respectively a plurality of time intervals, and in that the longitudinally adjacent apertures are arranged in horizontally spaced and vertical ly staggered relation to each other across the Width of each longitudinal channel provided in the space between the face portion and the spaced back portion of the device, and in that a plurality of spacer members are provided between said face portion and said back portion and act as partitions to separate the said space into a plurality of separate longitudinal channels.

6. A computing device as claimed in claim 1 and further characterized in that six vertical columns of apertures are provided to represent respectively six time intervals, and that the longL tudinally adjacent apertures are arranged in staggered relation to each other, and in that the data provided on each slide member is arranged in a plurality of separate columns extending 1ongitudinally of the member in staggered Columns so spaced with relation to said apertures that preselected data will be displayed through said apertures upon adjustment of said slide members therein.

7. A computing device as claimed in claim 1 and further characterized in that six vertical columns of apertures are provided to represent respectively six time intervals and in that the longitudinally adjacent apertures in said column are arranged in staggered relation to each other, and

inthat the body portion comprises a face portion and a back portion secured inspaced relation to each other by a plurality of longitudinally extending spacer members which act as partitions to divide said space into a plurality of separate longitudinal channels, and in which the data is arranged in a pluralityY of separate co1- umns extending longitudinally of each slide member and in staggered vertical columns spaced with relation to said staggered apertures to display the desired data in said aperture upon longitudinal adjustment of said slide member.

QUENTIN M. KLINE. 

